Thermal effect on frequencies of coupled vibrations of a rotating beam of linearly varying semi-circular cross-section

An analysis is presented of the effect of a constant thermal gradient on coupled vibrations of a beam of linearly varying semi-circular cross-section attached to a rotating disc. A method based on Rayleigh's quotient is used to obtain upper bounds of the frequencies corresponding to the first three modes of vibrations. The frequencies for various values of cross-section variation, hub-radius and temperature gradient are obtained.     

Complete and incomplete fusion in12C+93Nb and16O+89Y reactions

Excitation functions for the evaporation residues for the reactions¹²C+⁹³Nb and¹⁶O+⁸⁹Y in the projectile energy range of 4 to 6.5 MeV/amu have been measured using off-line gamma spectrometry. The excitation functions for neutron(xn), proton(pxn) and one alpha(xn) emission channels are practically similar for both the reactions. However the products formed by two alpha(2xn) emission show much higher cross sections in the¹²C+⁹³Nb than the¹⁶O+⁸⁹Y system. This has been explained in terms of the incomplete fusion process involving transfer of an alpha particle from the projectile to the target in the former case.Authors thank Shri D.C. Ephraim for making the rolled metal foils and the operation crew of PELLETRON facility for their help in carrying out the irradiations. Authors are grateful to Dr. P.R. Natarajan, Head Radiochemistry Division for his keen interest in this work.     

Mass resolved angular distribution in helium ion induced fission of233U

Mass resolved fission fragment angular distribution was measured in the 28.5 MeV alpha induced fission of²³³U using recoil catcher technique and direct gamma spectrometry. The angular distribution of 8 fission products were obtained. The angular anisotropies of asymmetric fission products were found to be higher than those of symmetric products indicating a correlation between the fragment angular distribution and the mass distribution.The authors are grateful to Dr. S.K. Kataria and Dr. T. Datta for fruitful discussions. We thank the operation crew of the variable energy cyclotron, Calcutta for their help in carrying out the irradiations. Thanks are due to Dr. P.R. Natarajan, Head of the Radiochemistry Division for his keen interest in the work.     

Sodium diffusion in sodium borosilicate glass used for immobilization of high level liquid waste

Diffusion of sodium in Mn and Ti bearing sodium borosilicate glass used for the immobilization of the high level waste at the Waste Immobilization Plant, Tarapur has been studied by heterogeneous isotopic exchange using ²⁴Na as the radiotracer for sodium. The temperature dependence of the self-diffusion coefficient of sodium in the glass was found to follow Arrhenius equation below the glass transition temperature.     

Permanently oriented antibody immobilization for digoxin determination with a flow-through fluoroimmunosensor

This paper reports a new flow-through fluoroimmunosensor, the function of which is based on antibodies immobilized on an inmunoreactor of controlled-pore glass (CPG), for determination of digoxin, used in the treatment of congestive heart failure and artery disease. The immunosensor has a detection limit of 1.20 microg L(-1) and provides high reproducibility (RSD=4.5% for a concentration of 0.0025 mg L(-1), and RSD=6.7% for 0.01 mg L(-1)). The optimum working concentration range was found to be 1.2 x 10(-3)-4.0 x 10(-2) mg L(-1). The lifetime of the immunosensor was about 50 immunoassays; if stored unused its lifetime can be extended to three months. A sample speed of about 10-12 samples per hour can be attained. Possible interference from substances with structures similar to digoxin (morphine, heroin, tebaine, codeine, pentazocine and narcotine) was investigated. No cross-reactivity was seen at the highest digoxin: interferent ratio studied (1:100). The proposed fluoroimmunosensor was successfully used to determine digoxin concentrations in human serum samples.     

Synthesis and characterization of zeolite Linde Type W and its metal oxide composite Ag-O-LTW used for the decontamination of chemical warfare agent simulant

Abstract

In this study, we have evaluated the performance of novel adsorbent zeolite Linde Type W and modified LTW with AgO metal oxide composite for the decontamination of chemical warfare agent simulant 2-chloroethylphenylsulphide (CEPS). Zeolites are nanoporous aluminosilicate minerals composed of silicon, aluminum and oxygen framework with cations and water molecules within the pores. The synthesized zeolite LTW and its composites Ag-O-LTW was characterized by XRD, FTIR, SEM-EDS and BET analytical techniques. The decontamination study of CWA simulant, CEPS was monitored by using GC-FID technique. The nanocrystalline zeolite LTW and Ag-O-LTW composites were found powerful adsorbents and showed great decontamination potential toward CWA simulant CEPS. The Ag-O-LTW showed better results (～98 % decontamination in 7?hours) than LTW zeolite.     

Determination of 90Sr in environmental samples using solid phase extraction chromatography

The p-tert-butyl calix[4]arene thiophenol derivative was successfully synthesized with reflux condition and was characterized by FT-IR and ¹H-NMR. This work mainly adopted the method of controlling variables. The results showed that the optimum pH value, temperature and extraction time were respectively 4.5, 25 °C and 90 min. By calculating the data of the enthalpy change and gibbs free energy, indicating that the process of reaction was an exothermic and spontaneous process, and it demonstrated a close agreement with pseudo-second-order kinetic model. It is also found that the coexisting cations on the extraction of uranium had greater influence.

     

Investigate oxoazolidine-2,4-dione based eutectic mixture via DFT calculations and SAR

In this work, DFT calculations for the designed eutectic mixtures (EMs) using oxoazolidine 2,4-dione (OZD) and zinc chloride (ZnCl2) are done. The interaction between the hydrogen bond donor and hydrogen bond acceptor at atomic level to get EMs are studied using DFT calculations. At room temperature, the stability of these various systems have been investigated using thermodynamic values or parameters such as enthalpy, free energy and others. DFT calculations is used to investigate the possibility of forming the systems (EMs). Further, the impact of varying the temperature on each system was also investigated (323K, 348K). Various other thermodynamic parameters are studied like dipole moment, hardness, chemical potential of the systems (individual molecules and EMs) at different temperatures. The results of the calculations showed that O1Z4 and O4Z1 have maximum dipole moment having values 8.1291, 9.8801 respectively, indicating maximum polarizability. Change in free energy for O1Z4 is least and was found to be ?37.2496 kcal/ mol. Further on changing the temperature, the parameters do not show much variation. Additionally, we have analyzed structure activity relationship (SAR) method to understand the physico-chemical properties of designed EMs and predict their regression and correlation to optimized energy. From the calculated values of pOE model, the value of r² is 0.9995 confirms the validity of the equation obtained. The results of this study suggest a link between the structures that have been utilized to describe the intermolecular interaction between the hydrogen bond donor and acceptor, as well as the stability of the EMs.     

Exact Controllability of a Semilinear Thermoelastic System with Control Solely in Thermal Equation

A result concerning the exact controllability of a semilinear thermoelastic system, in which the control term occurs solely in the thermal equation, is derived under the influence of rotational inertia and Lipschitz nonlinearity, subject to the clamped/Dirichlet boundary conditions. In the proof, we make use of the result given by Avalos (Differential and Integral Equations, 2000; 13(4–6):613–630), which states that the corresponding linear system is exact controllable.     

After effects of β− on time differential perturbed angular correlation spectra

The after effects of β⁻ -decay on time differential perturbed angular correlation (TDPAC) spectra of II–VI semiconductor CdS have been studied using β⁻ -emitting¹¹¹Ag as well as^111mCd as probe nuclei. The TDPAC spectrum of¹¹¹Ag in CdS exhibits a time dependent interaction indicating that the preceding β⁻ -decay leaves the daughter nucleus in an excited state. The recovery time (τ_g) of the probe atom was found to be 16±6 ns while Abragam and Pound's relaxation time (τ_kr) was found to be 9±2 ns. The results show that β⁻ -decay does change the chemical environment around the probe atom.